The pelvis is a bony structure located in the lower abdomen that supports the spine and provides attachment points for the legs. The three parts of the pelvis are the sacra, HIPBONES, and ilia. The sacra is a group of five fused vertebrae located at the base of the spine. The HIPBONES, also known as the innominate bones, are two large bones that form the sides of the pelvis. The ilia are two large, flat bones located at the top of the HIPBONES. Together, these three parts of the pelvis provide support and stability to the body.